Using cephalic furrow formation during Drosophila embryogenesis as a model, l plan to analyze morphogenesis at a cellular, genetic, and molecular level. This system will allow the detailed study of cell shape changes and cell movements and their regulation during development. The cell shape changes and movements that occur during cephalic furrow formation will be characterized at the cellular level. The role of segmentation genes in controlling this process will be better defined. Genetic analysis will allow the identification of zygotic genes that act downstream of the segmentation genes to regulate this process. The analysis of this morphogenetic process will be extended to the molecular level by cloning one of these genes. In addition, experiments will be conducted to test the feasibility of using surgical manipulations to analyze morphogenesis in Drosophila embryos. This combined approach should provide a detailed understanding of certain aspects of morphogenesis.